Physical Society Colloquium

Sugar coatings, slow-motion videos, and THz photonics to unveil the dynamics of quantum organic materials

Jean-Michel Ménard

Department of Physics
University of Ottawa

Terahertz (THz) radiation, located in the deep infrared region of the electromagnetic spectrum, can interact with molecules through their low-energy vibrational and rotational modes. During the last two decades, THz spectroscopy has been increasingly used to trace molecular dynamics and improve our understanding of key biological functions. In parallel, THz technologies have been developed for industry to identify specific molecular compounds for quality control and medical diagnostics. More recently, the intersection of THz photonics and quantum technologies has attracted increasing attention. Our research group is particularly interested to contribute to these advances from both the quantum photonics and quantum materials side. In this talk I will present an efficient technique for synthesizing quantum organic materials by combining THz light and matter. We design and fabricate a two-dimensional planar resonator, a metasurface, that effectively traps light. Using a spray coating technique, a thin glucose layer is deposited on that metasurface to induce a strong interaction between confined light and glucose molecules in sugar. We then maximize light-matter interaction strength by engineering a new cavity architecture combining the traditional planar cavity design with metasurface resonators [1]. The resulting quantum molecular system exhibits unique properties, which are of interest because of their potential applications in chemistry, biology and medicine. Since organic materials often display irreversible and non-reproducible dynamics, we also developed, in parallel, a real-time THz monitoring system to replace the standard time-resolved THz spectroscopy technique, intrinsically relying on multiple data point averaging. Using a combination of nonlinear optical effects, optical fibers, and fast electronics, we can now record THz transients at a rate of 1 MHz, a speed only limited by the repetition rate of our laser [2, 3]. Our ultimate goal is to use this new probing technique to investigate the dynamics of quantum organic materials and, especially, investigate for the first time how this dynamics can be affected by a regime of strong light-matter coupling.

[1] A. Jaber, M. Reitz, A. Singh, A. Maleki, Y. Xin, B. T. Sullivan, K. Dolgaleva, R. W. Boyd, C. Genes, J.-M. Ménard. Hybrid architectures for terahertz molecular polaritonics. Nature Communications 15, 4427 (2024)
[2] N. Couture, M. Lippl, W. Cui, A. Gamouras, N. Joly, J.-M. Ménard. Performance analysis of table-top single-pulse terahertz detection at rates up to 1.1 MHz. Physics Review Applied 21, 054020 (2024)
[3] N. Couture, W. Cui, M. Lippl, R. Ostic, D. J. Jubgang Fandio, E. K. Yalavarthi, A. V. Radhan, A. Gamouras, N. Joly, J.-M. Ménard. Single-pulse terahertz spectroscopy monitoring sub-millisecond time dynamics at a rate of 50 kHz. Nature Communications 14, 2595 (2023)